The present invention is directed to razor heads such as shaving cartridges and, more particularly, to razor heads comprising intermediate guard elements.
Many razor heads found on the market have a guard member disposed forwardly of the cutting edges of two blades and a cap member. Each of these four elements contact the skin surface during shaving and, therefore, are often referred to as xe2x80x9cskin-engagingxe2x80x9d elements. In a typical safety razor, these four skin-engaging elements are disposed in a spaced relation such that a small space is provided between the guard member and the first blade edge, another space is provided between the two blade edges, and another space may be provided between the second blade edge and the skin-engaging portion of the cap member. Such spaces are typically provided between the skin-engaging portions of these four elements, though not necessarily between other portions of these elements which do not contact the skin. For example, the forward or xe2x80x9cseatxe2x80x9d blade may be attached directly to the guard member at a point remote from the cutting edge of the seat blade but a space would typically be provided between the skin-engaging surface of the guard member and the sharpened edge of the seat blade.
Though it has been formerly recognized that the relative positioning and spacing of the skin-engaging portions of these skin-engaging elements affects the flow of skin across the cutting edges of the blades as well as the shaving angle at which the skin contacts the blade edges, it is desirable to provide still greater skin flow control.
A relatively recent improvement to the field of wet shaving relating to the control of skin as it flows between blades is the use of wire wrapped blades. Wire wrapped blades comprise at least one metal wire wrapped, in spaced intervals, around the sharpened leading edge of a plurality of blades to limit the amount of skin that can flow between the blades.
The use of wires to wrap blades provides an advantage during shaving, however, manufacturing is inherently complicated by the need to position the wires relative to the blade edges. Additionally, previously known wire wrapped blades have utilized a single size wire with a constant diameter which places limitations upon the shape and contour of the guard elements spaced along the cutting edge of the blades. Additionally, it can be difficult to secure wire guard elements across the cutting edge of a blade in a razor head. These wires also do not significantly inhibit movement of the blade edges in a direction perpendicular to a shaving stroke during shaving.
Therefore, it would be desirable to provide razor heads with improved skin flow controls which are easier to manufacture, relatively inexpensive to manufacture, which provide greater design flexibility for controlling skin as it flows over the cutting edges of one or, more blades during shaving, and which permit greater flexibility of the entire razor head during shaving.
The various aspects of the present invention are directed to novel skin-engaging elements for razor heads including their design, construction and manufacture. The various aspects of the present invention are designed to provide a razor head which enables a safe, close and comfortable shave while facilitating an easier, more reproducible and less expensive manufacturing process and which provides greater design flexibility with respect to the size and positioning of guard elements, shaving aids and high coefficient of friction materials relative to the blades. Additionally, disclosed embodiments are also designed to facilitate the easy removal of shaving debris which may accumulate in spaces of razor heads of the present invention.
One embodiment of the present invention is a razor head comprising at least one blade having a first end, a second end, discrete portions intermediate the ends, and a leading edge. A plurality of guard elements are molded over and engage and cover the leading edge of the blade at a plurality of locations intermediate the ends of the blade and separate the discrete portions of the blade from each other. According to preferred embodiments of the present invention, the molded guard elements are integrally molded with one or more of a blade support, spacer element(s), forward guard member(s) or cap member(s). It is believed that the use of integrally molded guard elements, especially when the guard elements are integrally molded with blade supports or spacers, provide greater blade stability and allow less relative movement of the blade edges than wire wrapped blades since the molded guard elements tend to hold the blades in position more rigidly when the blades encounter hair during a shaving stroke. Those skilled in the art will appreciate that it is desirable to maintain predetermined blade spacing during shaving. Relative movements of the blade edges during shaving which significantly change the edge to edge spacing can result in a less than optimum shave. The various embodiments of the present invention also provide greater design flexibility in the size and shape of the intermediate guard elements. For example, the intermediate guard elements can readily extend outwardly from the blade edge any desired distance and a single razor head can readily be provided with guard elements which extend different distances from the edge of one blade or the edges of different blades.
Additionally, in preferred embodiments, when the molded guard elements are aligned with spacers, these guard elements do not inhibit the rinsability of the razor head.
The various embodiments of the present invention also advantageously provide additional sites for the placement of shaving aids and other skin flow control materials such as materials having high or low coefficients of friction.
Other aspects of the present invention comprise methods of manufacturing razor heads. One preferred method comprises insert molding a razor head with a blade support, forward guard member, cap member, spacers and novel guard elements integrally molded in a single or sequential molding process.
Other methods of the present invention comprise sequentially molding shaving aids and resilient skin engaging materials having high or low coefficients of friction onto the various skin engaging elements of the disclosed razor heads.